4.2.8-ckt2 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
commit 02e2a5bfebe99edcf9d694575a75032d53fe1b73 upstream.
If md->signature == MAC_DRIVER_MAGIC and md->block_size == 1023, a single
512 byte sector would be read (secsize / 512). However the partition
structure would be located past the end of the buffer (secsize % 512).
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
block/partitions/mac.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/block/partitions/mac.c b/block/partitions/mac.c
index c2c48ec..621317a 100644
--- a/block/partitions/mac.c
+++ b/block/partitions/mac.c
@@ -32,7 +32,7 @@ int mac_partition(struct parsed_partitions *state)
Sector sect;
unsigned char *data;
int slot, blocks_in_map;
- unsigned secsize;
+ unsigned secsize, datasize, partoffset;
#ifdef CONFIG_PPC_PMAC
int found_root = 0;
int found_root_goodness = 0;
@@ -50,10 +50,14 @@ int mac_partition(struct parsed_partitions *state)
}
secsize = be16_to_cpu(md->block_size);
put_dev_sector(sect);
- data = read_part_sector(state, secsize/512, §);
+ datasize = round_down(secsize, 512);
+ data = read_part_sector(state, datasize / 512, §);
if (!data)
return -1;
- part = (struct mac_partition *) (data + secsize%512);
+ partoffset = secsize % 512;
+ if (partoffset + sizeof(*part) > datasize)
+ return -1;
+ part = (struct mac_partition *) (data + partoffset);
if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) {
put_dev_sector(sect);
return 0; /* not a MacOS disk */
--
1.9.1
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